528 MANUAL OF ZOOLOGY SECT. 



lower surface is covered with hair only. The jaws are pro- 

 duced into a rostrum which is much narrower than that of 

 Ornithorhynchus. The eyes are small, and there is no audi- 

 tory pinna. The tail is vestigial. 



The opossums (Didelphyida) (Fig. 316) are arboreal 

 rat-like marsupials, with elongated naked muzzle, with well- 

 developed, though nailless, opposable hallux, and elongated 

 prehensile tail. The Dasyuridae (Australian native cats, 

 tasmanian devil, thylacine, etc.) have the pollex often rudi- 



FIG. 316. Virginian Opossum (Didelphys virginiana}. (After Vogt and Specht.) 



mentary, the foot four-toed, the hallux, when present, small 

 and clawless, and the tail not prehensile. 



The bandicoots (PerameKdas) are burrowing marsupials, 

 the size of which varies from that of a large rat to that of 

 a rabbit. They have an elongated pointed muzzle, and, in 

 some cases, large auditory pinnae. The first and fifth digits 

 of the fore-foot are vestigial or absent, the remaining three 



